I've seen "normal" slides with the hands up where there's clearly no intent to interfere and no one says a word. I've seen slides with the hands up where there's clearly intent to at least put some kind of thought into F4/6's head that there might be something in the way.
A. On the line is more-preferable than off the line. Both are used. B. Why didn't you discuss it between games "Hey -- I noticed you were on the lne. I'm usually off the line. What's your thought process on being there? I prefer off the line because, ...."
Maybe you're right. I see him with his hands up, and I thought he was making (or about to make) the OBS / award call, but maybe it's just the "dead ball" (sic) call. If U3 doesn't have the call, I'd give first crack to PU. Not a big deal since there are no other runners and all the umpires should have an opinion on the play (this one is obvious, but you can conceive of a similar play where maybe some discussion is needed), but I'd rather U2 wait to see if U3 / PU had it before stepping up with the point.
I hate to disagree with Maven, but I have to this time.
As I read your phrasing, I do NOT think it's identical to the rule; and I disagree with your ruling in your example (BR 3' from second being returned to first). I did not go back and re-watch the OP, so I have no comment on the ruling in that play.